Overview Medium Voltage Power Supplies

A transformer is used to transform the mains supply to high voltage. Either on the primary side or on the secondary side of this transformer a phase controlled thyristor rectifier circuit is fitted. A series LC filter is used to smooth the resulting rectified voltage.

In principle, the rectified line voltage drives a square wave generator of fixed frequency, whose AC voltage is transformed, rectified and filtered, producing the output voltage. For regulation, the square wave voltage is pulse width modulated. A low residual ripple of the output voltage, together with a high stability, high regulation speed and a low stored energy are all achieved by virtue of the high switching frequency.